The present invention relates to a semiconductor device and a manufacturing method therefor, and is suitably applicable to a semiconductor device equipped with an insulated gate bipolar transistor (IGBT), for example.
A trench gate type IGBT has widely been used as an IGBT low in on resistance, i.e., an IGBT low in forward saturation voltage Vce (sat). There has been developed an IE type IGBT which makes an IE (Injection Enhancement) effect available by alternately arranging an active cell area having a gate electrode for a gate potential electrode, and an emitter region for an emitter potential electrode, and an inactive cell area including a p-type floating region. The IE effect is intended to make positive holes harder to be discharged from the emitter potential electrode side when the IGBT is in an on state, to thereby enhance the concentration of an electric charge accumulated in a drift region.
There has been disclosed in Japanese Unexamined Patent Application Publication No. 2013-140885 (Patent Document 1), an IE type IGBT having a structure (GGEE type structure) in which two trench gates adjacent to each other are respectively coupled to an emitter potential in addition to a GG structure in place of an IE type IGBT having a structure (GG type structure) in which two trench gates adjacent to each other are respectively coupled to a gate potential.
There has been disclosed in FIG. 4 of International Publication No. 2015/022989 (Patent Document 2), a technology of narrowing between trench gates coupled to an emitter potential in a GGEE type structure and separating the trench gates coupled to the emitter potential in a direction in which the trench gates extend.
There has been disclosed in Japanese Unexamined Patent Application Publication No. 2016-184622 (Patent Document 3), a problem that a displacement current is generated through a gate due to a potential fluctuation in a floating region in an EGE type structure being a structure similar to the GG type structure and the GGEE type structure.